Security context

What an agent needs to avoid regressing past fixes and find the next vuln in this repo.

yaml/pyyaml

              main @ 34a9bf8
            

Fixes

CVEs

CRITICAL

Peak severity

72.7%

Coverage

Highlights

Remote Code Execution: 5 prior fixes. Scrutinize any change in this area.

lib/yaml/constructor.py: most-fixed (4 issues). Treat as high-risk during review.

9 high-severity fixes in this history; regressions here are high-impact.

Recurring patterns

The bug types that recur here, drawn from past fixes, not open vulnerabilities.

Remote Code Execution: Unsafe default loading configurations in `yaml.load()` historically allowed arbitrary Python code execution during parsing of untrusted YAML input, requiring the API to transition to safer defaults.

Arbitrary Code Execution: The parsing of custom Python object tags (such as `python/object/new` and `python/object/apply`) under `FullLoader` bypassed restrictions, leading to full RCE and requiring these constructors to be quarantined.

Denial of Service: The mapping flattening process during YAML merge key handling was vulnerable to exponential complexity exploits when processing highly nested or duplicate node references.